General protractor.



J. SHARPB.

GENERAL PROTRAGTOR.

APPLIOATIONAHLED JULY19, 1912.

1,058,474. Patented Apr. s, 1913.

576295161517 33 30 27 zig A JOSEPH SHARPE, OF FORT HUACHUCA, ARIZONA.

GENERAL PROTRACTOR.

Specification of Letters Patent.

Patented Apr. 8, 1913.

Application le'd July 19, 1912. Serial No. 710,527.

To all wiz-0m t may concern.'

Be it known that l, Josnrii Si-iAnrii7 a citizen of the United States,residing at Fort Huachuca, in the county of Cochise, State of Arizona,have invented certain new and useful Improvements in GeneralProtractors; and I do hereby declare the following to be a full, clear7and exact descrip\ tion of the invention, such as will enable othersskilled in the art to which it appertains to make and use the same.

This invention relates to preti-actors.

The object of the invention resides in the provision of a protractorthrough the instrumentality of which various problems in civil andmechanical engineering may be solved wit-hout resorting to complicatedmathematical calculation. j

A further object of the invention resides in the provision of aprotractor which will have a wide field of usefulness and which will besimple in construction, easy of use and which may be manufactured at acomparatively small cost.

Wvith the above objects in view, the in vention consists in the detailsof construe` tion and in the arrangement and combination of parts to behereinafter more fully described and particularly pointed out in theappended claims.

ln describing the invention in detail reference will be had to theaccompanying drawings wherein like characters of reference denotecorresponding part-s in the sev* eral views, and in which- Figure 1 is aplan view of the protrae-tor, Fig. 2, a section on the line 2-2 of Fig.1, Fig. 3, a section on the line 3dS of Fig. 1, Fig. 4, a section on theline 4 4 of Fig. 1, Fig. 5, a section on the line 5 5 of Fig. 1, andFig. 6,. a section on the line 6 6 of Fig. 1.

Referring to the drawings the instrument is shown as comprising a baseor body A having adjacent sides 10 and 11 thereof disposed at rightangles to each other and provided with graduations 13 and 14respectively7 said graduations being similar in nature and reading fromthe point of intersection of the sides 10 and 11 outwardly. The body Ais provided with a circular opening 15 the wall of which is recessedthroughout its entire length as at 16. Disposed within the opening 15 ofthe body A is a ring 17 the outer edge of which is pro` vided with aflange 18 which seats in the recess 16. The ring 17 is held againstdisengagement from the base A by means of a securing ring 19 suitablyattached to the bottom of the base A and overlapping the flange 18 ofthe ring 17. By this construction it will be apparent that not only isthe ring 17 secured against disengagement from the base A but is alsofree to rotate axially. The face of the base A surrounding the opening15 is provided with graduations representing the degrees of a circlehaving `its center coincident with the axis of the ring 17. The inneredge of the ring 17 is connected at opposite points by a diametri calcross bar 21 and the center of this cross bar is connected to the inneredge of the ring 17 by a radial cross bar 22 disposed, at right anglesto the cross bar 21. It will be here noted with respect to thediametrical cross bar 21 that the side thereof adjacent the radial crossbar 22 is beveled as at 23 and provided with graduations 24 reading fromthe center of said bar outwardly. It will be further noted that the sideofthe `diametrical cross bar 21 adjacent the radial .graduations 26reading from the inner end of said radial cross bar outward. Mountedupon the base A along the side thereof opposite the side 10 and parallelto said latter side is a plate 27 provided with graduations 28, saidgraduations beginning at a point in line with the side edge of the bar24 which coincides with a diameter of the ring 17 The plate 27 issupported in spaced relation to the base A /by means of blocks 29disposed between the terminals of said plate and the base A. Slidablebetween the plate 27 and base A is one end of an elongated plate 30which is disposed parallel to the side 11 of the base and has the sidethereof adjacent said side 11 beveled and provided with graduations 31.These graduations 31 read from a point in the plane of the graduatedside edge of the radial bar 26 outwardly toward each end of the plate30. The plate 3() just inward of the plate 27 is provided with a rib 32which bears against the inner edge of the plate 27 while the extremeouter end of the plate 30 is provided with a cross arm 33 which bearsagainst the outer side of the plate 27 and4 the adjacent side of thebase A. The graduated side edge of the plate 31 is extended across therib 32 by means of a line 34 whereby said graduated side edge of theplate 30 may be brought into registration with any of the graduationsupon the plate 27 with certainty. Mounted in the rib 32 is a clalnpingscrew 35 which is adapted to bear upon the adjacent face of the base Aand thereby secure the plate 30 in any desired adjust-ment with respectto the plate 27. Mounted in the body A is another ad` justing screw 36which is adapted to bear upon the ilange 18 and thereby secure the ring17 against rotation on its aXis. The ring 17 is provided on its upperface at op posite points with transverse lines 36 and 37 which registerwith the graduated side edge of the radial'cross arm 26. Said ring 17 isalso provided on its upper face at opposite points with lines 3S and 39which register with the graduated side edge of the diametrical cross bar24.

What is claimed is:

1. A protractor comprising a base, a ring rotatably mounted in said basethe latter being provided with graduations surrounding said ring, adiametrical cross bar connecting the opposite sides of the inner edge ofthe ring and having one side edge graduated and disposed coincident witha given diameter of the ring, a radial cross arm disposed at rightangles to the diametrical cross arm and connecting the latter with theinner edge of the ring, said radial cross arm having one side edgegraduated and disposed coincident with a given radius of the ring, agraduated plate mounted on the upper face of the base in spaced relationto the latter, a graduated arm having one end slidabl mounted betweenthe plate and the base, and means for locking said arm against slidingmovement.

2. A protractor comprising a base, a ring rotatably mounted in saidbase, the latter being provided with graduations surrounding said ring,means for locking said ring against rotation, a diametrical cross barconnecting the opposite sides of the inner edge of the ring and havingone side edge graduated and disposed coincident with a given diameter ofthe ring, a radial cross arm disposed at right angles to the diametricalcross arm and connecting the latter with the inner edge of the ring,said radial cross arm having one side edge graduated and disposedcoincident with a given radius of the ring, a graduated plate mounted onthe upper' face of the base in spaced relation to the latter, agraduated arm having one end slidably mounted between the plate and thebase, and means for locking said arm against sliding movement.

3. A protractor comprising a base having a pair of adjacent side edgesdisposed at right angles to each other and provided with graduations,reading from their point ofintersection outwardly, a ring rotatablymounted in said base, the latter being provided with graduationssurrounding the ring, a diametrical cross bar connecting the oppositesides of the inner edge of the ring and having one side edge graduatedand disposed coincident with a given diameter of the ring, and a radialcross arm disposed at right angles to the diametrical cross arm andconnecting the latter with the inner edge of the ring, said radial crossarm having one side edge graduated and disposed coincident with a givenradius of the ring.

In testimony whereof, I aiix my signature, in presence of two witnesses.

JOSEPH SHARPE. lVitnesses:

JOHN H. CHAPPLE, EUGENE A. LA FLAME.

Copies of this patent may be obtained for ve cents each, by addressingthe Commissioner of Patents. Washington, D. C.

